Received used G19 yesterday from dealer with 3 day inspection - "2nd Generation" (no finger grooves - front & rear checkering). Went to range (after cleaning and lubing) and found that slide won't go into battery like it should. Sometimes it will go fully into battery after I release the trigger and other times I have to literally reach up with my thumb and push the slide forward for the last 1/4". * FIRST ASSUMPTION was that recoil spring is weak. But I tried two new guide rods that work fine in my other Glocks - problem didn't go away. * THEN I took the slide off the pistol and put it on the frame of one of my other Glocks. WORKED PERFECTLY - so I figure I've at least isolated the problem to being somewhere in the frame. * THEN (since it APPEARED that the trigger bar was dragging on the firing pin safety plunger as it would try to go back into battery) I removed the entire trigger assembly and dropped in a trigger assembly from one of my other Glocks (and tried it with the original slide). STILL WON"T GO INTO BATTERY. SO the problem appears to be in the frame, but not in the trigger assembly. Rails look fine (this is NOT an "E" serial number). What am I overlooking ? FWIW The dealer is willing to take the pistol back, and I know I can send it to Glock (spoke with them yesterday - no suggestions on a cure)but I don't know how long that will take (especially if they have to order a replacement frame). But I would like to make it work - only paid $330 for the G19 in perfect cosmetic condition, Trijicon night sights and a 15 round factory mag.